Television antenna



Sept' 21, 1954 R. R. WILLIAMS TELEVISION ANTENNA 2 Shee'ts-Sheet 1 Filed Sept. 5, 1952 Eis/suda FIG. 2. 4

FIG. 3.

Sept 21, 1954 R. R. WILLIAMS 2,689,912

TELEVISION ANTENNA- Filed sept. 5, 1952 2 sheets-sheet 2 an aperture 32 in the top wall H of the housing and a turning knob 33 is mounted on the upper end of the shaft 25 above the upper surface of the housing top wall I4, so that the drum 263 can loe manually rotated about the axis of the shaft 25 for a purpose to be presently described.

One or more loop type antennas are mounted on the drum 25 and these antennas yare of relatively diierent lengths to 'cover different selected wave length ranges of broadcast signals.

In the arrangement illustrated there are two antennas as generally indicated at 35 and 36 of which the antenna 35 is longer than the antenna 36. Both of the antennas comprise elongated ribbons or wires of flexible, electrically conductive material, such as sheet copper, wound in spiral fashion around the side wall 2| of the drum, each antenna comprising a plurality of loops each of which extends over the opposite ends of the side wall 2i and along the inner and outer sides thereof. The loops are spaced apart a distance no greater than the width of the ribbon and are wound onto the side wall of the drum before the end walls are secured in place in the corresponding ends of the side wall. The longer antenna 35, when wound on a drum of the dimensions indicated above, should comprise a length of wire or ribbon at least ten feet long for television channels and the shorter antenna 35 may comprise a length of ribbon or wire approximately ve feet long and has its ends spaced suciently from the ends of the antenna 35, so that no interference is set up between the two antennas.

A pair of arcuately curved commutator bars 3l and 38 are disposed against the under side of the bottom end wall 23 of the drum concentric with the axis oi the shaft 24 and spaced from each other and these commutator bars have an angular extent substantially the same as the angular extent of the antenna 35 around the drum. Two similar commutator bars 39 and 40 are also mounted on the bottom surface of the bottom end wall 23 of the drum concentric with the axis of the shaft 24 and in spaced apart relationship to each other and these bars have an angular extent coincident with the angular extent oi' the shorter antenna 36.

Commutator brushes il and 42 in the form of thin strips of resilient metal are mounted on the bearing plate il and extend outwardly of the cylindrical surface of the drum toward the end Wall i3 of the housing I0. These brushes extend one from the inner and one from the outer commutator bar outwardly of the drum 25 and antenna lead-in wires 43 and 44 are connected one to each or these brushes.

A partly cylindrical shield 45 of electrically conductive and preferably magnetic material extends around a portion of the drum 25 in spaced relationship to the outer surface of the side wall of the drum. rEhe shield 45 has an angular extent at least as great as the angular extent of the longer antenna 35 around the drum and has a width substantially as great as the length of the drum. This shield may be rmly mounted on the base l2 by means of a semicircularly curved bar d6 of insulating material of rectangular cross sectional shape, secured on the upper surface of the base i2 and having in its upper surface a longitudinally extending groove 4'] which receives the lower edge of the shield 45 which shield is of elongated, rectangular cross sectional shape. While the shield is illustrated as disposed outside the drum, it is to be understood that it may be disposed inside the drum or that two shields, one disposed outside and the other disposed inside the drum may be used, without in any way exceeding the scope of the invention.

The brushes il and 42 have on their inner ends upwardly curved portions 38 and 45 which contact the under sides of the commutator bars and are so located relative to the ends of the shield 45 that when one end of either of the antennas, for example, the antenna 35, begins to move past one end of the shield 45 with the remainder of the antenna disposed outside of the shield, the brushes will engage the corresponding ends of the bars 31 and 38 and the brushes will remain in contact with the commutator bars until the entire antenna is disposed within the angular extent of the shield. However, when the antenna starts out of the angular extent of the shield in the same direction of rotation, the brushes will leave the commutator bars and the antenna will no longer be connected into the circuit. Obviously, the angular extent of the antenna disposed within the angular extent of the shield 35 can be adjusted by rotating the drum 20 backwardly or forwardly with the brushes in engagement with the commutator bars 3'! and 38, so that either one loop or all of the loops or" the antenna may be disposed within the angular extent of the shield with the brushes in contact with the corresponding commutator bars.

The antenna 35 is connected at one end to lthe commutator bar 3'1 by a conductor 50, as

illustrated in Figure 5, and at its other end to the commutator bar 38 by a conductor 5l. The antenna 36 is correspondingly connected at its opposite ends to the commutator bars 35 and 40 by conductors 52 and 53.

A terminal block 55 is mounted on the upper surface of the base I2 at the corner between the side wall I6 and the end wall I3 and carries three terminal screws 56, 57 and 55 spaced apart longitudinally of the terminal block. A condenser 60 is mounted on the base l2 at a location spaced from the terminal block 55 and has two separate terminals 6I and 62 and a variable resistor S3 is mounted on the base at a location spaced from the condenser 50 and has separate terminals 64 and 65 and an adjusting knob or screw 66. For use as a television receiver antenna the condenser may have a value of approximately three hundred M. M. F. D. and the resistor may have a Value of approximately fty thousand ohms.

A conductor 68 is connected at one end to the terminal screw 5B and at its other end to the ungrounded wire of the two-wire extension cord which supplies electric energy to the associated receiver. This wire may be connected at its other end to the receiver terminal to which the corresponding power wire is connected and lead from the receiver terminal to the antenna terminal 55. The antenna terminal 56 is connected by a conductor 69 to the terminal 6i of the condenser 65 and the terminal 62 of the condenser B0 is connected by a conductor 'I0 to the terminal 5l of the resistor 63.

The condenser Si) blocks the alternating current from the electric power wire from reaching the resistor 65 while permitting short wave wireless signals on the power wire to reach the resistor. The other terminal 65 of the resistor is connected through a conductor 'H to the antenna lead-in wire 53 leading from the brush 4I to the receiving set and the magnetic shield 45 is also" connected at' one' endto the: lead-fin' wire 43" by a 'conductor l2. The lead-in wire '43ffro`m the'bru'sh 4|' leads tothe terminal screw lr'l and' the' lead-in wire 44' from' the brush" 4'2 leads to'- thete'rminal' screw 58. From the terminal screws l and- 58 the lead-in wires are continued to the associated receiver, as indicatedv at 'l-3'-` and. T4.

With the above described arrangement, short wave signals carried `on theV power wire A63 will be led to the' antenna lead-in wire 43 throughv the condenser 60 and variable resistor 63l and' willl also be led to the magnetic shield 45 and to one'end of the antenna 35l or 36 the commutator b'ars'- of which are in contact with theV brushes 4| and" 42 at the time. Simultaneously signals will be picked up directly by the operative antenna, the other end of whichv is connected' t'o the lead-iny wire 44 through the brush 4-2' andv the signals received' from the various' sources will be inductively correlated by the antenna' andV magneticshield and fed to the associated'rece'iver'as a correlated signal of improved streng'tll` and clarity.

lt has been found that in large buildings where' it is not practical to provide outside aerials or antennas for television receivers in the building' and where, consequently, inside antennas mustv be' relied upon, that the broadcast signal situation' in any room of such a building is usually highly complicated because of the' transmission of the signals along' conductive portions 'of the 'buildiing` structure, the plumbing conduits and the electricY wiring and the reflection oi the signals from various objects in the building 'or even 'in the room itself and from nearby' structures. Experimental use with the portable antenna oi the present invention 'has shown that even in a room in which there is such a complicated' signalV condition as that discussed above, the antenna of this invention can be adjusted to select a singlle strong signal free of out-of-phase signals in the same or any other channel and that it will receiveh different wave length signals from different directions with equal facility.

rIzhe invention may be embodied in other specific forms without departing from theA spirit or essential characteristics thereof. The present embodiment is, therefore, to be considered in all respects as illustrative and not restrictive, thesco'p'e of the invention being indicatedby the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are, therefore, intended to be embraced therein.

What is claimed is: 1

1. An antenna assembly for a short wave receiver comprising a base, a hollow cylindrical drum of electrically insulative material, means mounting said drum on said base for rotational movements of adjustment of said drum about its longitudinal center line as an axis, at least one antenna on said drum comprising a partly cylindrical winding of a strand of electrically conductive material wound around the wall of said drum from one end to the other of said drum and having a length corresponding to a predetermined portion of a selected wave length, arcuately shaped commutator bars mounted on one end of said drums concentric with the axis of rotation of the drum in spaced apart relationship to each other and connected one to one end and one to the other end of said antenna, brushes respectively engaging said commutator bars, lead-in wires extending one from each of said brushes for' connection to an associated re` ceiver, a' partly'y cylindrical' shield of electricallyconductive magnetic material extending partlyaroundfsaid drum and spaced therefrom, a con-- denser having separate terminals, a conductor extending from one condenser terminal for connection tol an electric power wire, a variableresistor' having separate terminals, a conductor connecting' one' of said resistor terminals' with' the'other' of saidv condenser terminals, and con-- ductor means connecting the` other resistor ter'- min'al with said' shield 'and with` one of said' lead-in wires'.

J2'. A short wave antenna assembly comprising' a base, va: hollow support of cylindrical shape and of electrically insulative material disposed.l above said base, means mounting said support on saidbase for rotational movementsl of adjustment about said longitudinal' center line as' an axis, atleast one antenna winding of electrically' conductive material spirally wound on said cylindrical support over th'e ends and along the inner and outer'si'des of said support, a pair of lead-in wires extending from said base for connecting the 'antenna assembly to an associated receiver, means connecting said lead-in wires 'one to each end of said antenna winding, a shield of electrically conductive material. and of partly cylindrical shape xedly mounted along one curved' edge thereof on said' base and extending partly around' said' support in spaced relationship thereto, conductor means connecting said shield to one of sai'd lead-in Wires, a condenser and a resistor connected together in a series, said 'resisto'r' being connected directly to said one lead-in wire, anda conductor extending from said con denser' for connecting the latter to an electric power wire.

3'. A short wave antenna assembly comprising Y .a base, a hollow support of cylindrical shape and' ofelectrically insulative material' disposed' above said base, means mounting said support on said base for rotational 'movements of adjustment about said longitudinal' center line as an axis, atleast one antenna winding of electrically conductive material spirally wound on said cylindri'cal support over the ends and along the inner and outer sides of said support, a pair of lead-in wires extending from said base for connecting the' vantenna assembly to an associated receiver, means connecting said lead-in wires one to each end of said antenna winding, a shield of electrically' conductive material' and of partly cylindrical shape xedly mounted along one curved edge' 'thereof on said base and extending partly around said support in spaced relationship thereto, conductor means connecting said shield to one of said lead-in wires, a condenser and a resistor connected together in series, said resistor being connected directly to said one lead-in wire, and a conductor extending from said condenser for connecting the latter to an electric power line, said shield being of elongated rectangular cross sectional shape and having a width between its curved edges substantially equal to the length of said support and a length such that it extends around said support to an angular extent substantially equal to the angular extent to which the longest antenna winding on said support extends around the support.

4. A short wave antenna assembly comprising a base, a hollow support of cylindrical shape and of electrically insulative material disposed above said base, means mounting said support on said base for rotational movements of adjustment about its longitudinal center line as an axis, antenna windings of electrically conductive material spirally Wound on said cylindrical support over the ends and along the inner and outer sides of said support in spaced relationship to each other and extending to respectively different angular extents around said support, a pair of lead-in wires extending from said base for connecting the antenna assembly to an associated receiver', means selectively connecting said lead-in wires to said antenna windings one to each end of the selected winding in accordance with the rotational position of adjustment of said support, a shield of electrically conductive material and of partly cylindrical shape xedly mounted along one curved edge thereof on said base and extending partly around said support in spaced relationship thereto, conductor means connecting said shield to one of said lead-in wires, a condenser and a resistor connected in series, said resistor being connected directly to said one lead-in wire, and a conductor extending from said condenser for connecting the latter to an electric power wire, said shield being of elongated rectangular cross sectional shape and having a width between its curved edges substantially equal to the length of said support and a length such that it extends around the support to an angular extent substantially equal to the angular extent at which the longest antenna winding on said support extends around the support.

5. A short wave antenna assembly comprising a base, a hollow support of cylindrical shape and of electrically insulative material disposed above said base, means mounting said support on said base for rotational movements of adjustment about its longitudinal center line as an axis, antenna windings of electrically conductive material spirally wound on said cylindrical support over the ends and along the inner and outer sides of said support in spaced relationship to each other and extending to respectively different angular extents around said support, a pair of lead-in wires extending from said base for connecting the antenna assembly to an associated receiver, means selectively connecting said leadin wires to said antenna windings one to each end of the selected winding in accordance with the rotational position of adjustment of said support, a shield of electrically conductive material and of partly cylindrical shape fixedly mounted along one curved edge thereof on said base and extending partly around said support in spaced relationship thereto, conductor means connecting said shield to one of said lead-in wires, a condenser and a resistor connected in series, said resistor being connected directly to said one leadin wire, and a conductor extending from said condenser for connecting the latter to an electric power wire, said shield being of elongated rectangular cross sectional shape and having a width between its curved edges substantially equal to the length of said support and a length such that it extends around the support to an angular extent substantially equal to the angular extent at which the longest antenna winding on said support extends around the support and said antenna assembly being freely portable and movable from place to place within the limits of the length of said lead-in wires while connected to an associated receiver.

6. An antenna assembly for a short wave receiver comprising a base, and antenna winding of a shape to constitute a portion of the wall of a hollow cylinder, means supporting said antenna winding on said base for rotational movements of adjustment of the winding about the axis of the complete hollow cylinder of which the shape of said winding constitutes a portion, lead-in wires connected one to each end of said antenna winding for connecting the winding to an associated receiver, a shield of electrically conductive material and of partly cylindrical shape xedly mounted on said base and spaced from the outer surface of the cylinder of which the shape of said antenna winding constitutes a portion, means electrically connecting said shield with one of said lead-in wires, a resistor and a condenser connected in series with said one lead-in wire, and conductor means connected to said condenser for connecting the latter to an elongated electrical conductor which constitutes a component of a building.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,719,893 Langley July 9, 1929 1,847,872 Hand Mar. 1, 1932 2,153,975 Smith et al. Apr. 1l, 1939 2,256,803 Houser Sept. 23, 1941 2,552,816 Root May 15, 1951 2,666,846 Davis Jan. 19, 1954 FOREIGN PATENTS Number Country Date 391,077 Great Britain Apr. 20, 1933 

